ABSTRACT
An ultralow program/erase voltage ( |VP/E| = 4 V) is demonstrated by using an antiferroelectric-ferroelectric field-effect transistor (AFE-FE-FET) through a multipeak coercive E -field ( EC ) concept for a four-level stable state with outstanding endurance (>105 cycles) and data retention (>104 s at 65 °C). The mixture of ferroelectric (FE) and AFE domains can provide stable multistate and data storage with zero bias for multilevel cell (MLC) applications. HfZrO2 (HZO) with AFE-FE assembles an orthorhombic/tetragonal (o/t) phase composition and is achieved by [Zr] modulation in an HZO system. MLC characteristics not only improve high-density nonvolatile memory (NVM) but are also beneficial to neuromorphic device applications.
Subject(s)
ElectricityABSTRACT
Ferroelectric (FE) Hf1-xZrxO2 is a potential candidate for emerging memory in artificial intelligence (AI) and neuromorphic computation due to its non-volatility for data storage with natural bi-stable characteristics. This study experimentally characterizes and demonstrates the FE and antiferroelectric (AFE) material properties, which are modulated from doped Zr incorporated in the HfO2-system, with a diode-junction current for memory operations. Unipolar operations on one of the two hysteretic polarization branch loops of the mixed FE and AFE material give a low program voltage of 3 V with an ON/OFF ratio >100. This also benefits the switching endurance, which reaches >109 cycles. A model based on the polarization switching and tunneling mechanisms is revealed in the (A)FE diode to explain the bipolar and unipolar sweeps. In addition, the proposed FE-AFE diode with Hf1-xZrxO2 has a superior cycling endurance and lower stimulation voltage compared to perovskite FE-diodes due to its scaling capability for resistive FE memory devices.
